Compact Laser Chiller Gets the Heat Out

Advances in diode pumping have led to smaller laser heads and smaller power supplies, meeting the growing demands for more compact, portable lasers. As a rule, diode-pumped devices are more efficient than traditional arc or flashlamp-pumped lasers in converting electrical input to light output, resulting in less waste heat for laser chillers to eliminate. The size of chillers, however, has not kept pace with other components.

In this Lightbook series laser (355, 532 or 1064 nm) from Light Solutions Corp., the laser head is about the size of a notebook computer; the power supply measures 12 × 12 x 6 in. Thermotek's compact T-250P chiller, also shown,measures 8 × 10.5 × 13.25 in.This has created challenges for companies like Light Solutions Corp., a manufacturer of diode-pumped solid-state lasers that are used as components in larger systems. "Everything is becoming smaller," said David Matthews, director of laser systems. "Our OEM customers especially want to integrate diode-pumped systems into their larger systems. They want the higher powers, but they want it in a smaller footprint. The Lightbook 10-W Nd:YVO4 laser head and power supply can provide that, but we've had a problem with finding a smaller chiller."

Light Solutions found a solution of its own in the form of the thermoelectrically cooled chiller from Thermotek Inc., which has shrunk the substantial size gap between chillers and other laser components. Thermotek's T-250P chiller measures 8 x 10.5 × 13.25 in. "Most standard chillers are 75 to 100 percent larger," Matthews said.

A nontraditional solution

Rather than relying on a traditional compressor system, Thermotek's 23-lb chiller instead uses thermoelectric technology to give Light Solutions' lasers a 250-W cooling capacity. Roger DeVilbiss, vice president of Thermotek, explained that the solid-state device uses proprietary technology that optimizes power consumption and requires only a 110-V wall plug to operate. "Our specialization is power application and control that we provide using thermoelectrics. Our niche is 50 to 500 W of cooling," DeVilbiss said.

Matthews pointed out that another advantage of solid-state chillers is that they are more reliable, requiring fewer components and less maintenance, and producing less noise. Smaller, more efficient diode-pumped, solid-state lasers also allow the use of closed-circuit water cooling such as the system incorporated into Thermotek's chiller, thus reducing water bills and increasing portability.